title: The X-ray crystal structure of APR-B, an atypical adenosine 5'-phosphosulfate reductase from Physcomitrella patens.
abstract: Sulfonucleotide reductases catalyse the first reductive step of sulfate assimilation. Their substrate specificities generally correlate with the requirement for a [Fe4S4] cluster, where adenosine 5'-phosphosulfate (APS) reductases possess a cluster and 3'-phosphoadenosine 5'-phosphosulfate reductases do not. The exception is the APR-B isoform of APS reductase from the moss Physcomitrella patens, which lacks a cluster. The crystal structure of APR-B, the first for a plant sulfonucleotide reductase, is consistent with a preference for APS. Structural conservation with bacterial APS reductase rules out a structural role for the cluster, but supports the contention that it enhances the activity of conventional APS reductases.
authors.affiliation: Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
authors.forename: Clare E M
authors.initials: CE
authors.lastname: Stevenson
authors.forename: Richard K
authors.initials: RK
authors.lastname: Hughes
authors.forename: Michael T
authors.initials: MT
authors.lastname: McManus
authors.forename: David M
authors.initials: DM
authors.lastname: Lawson
authors.forename: Stanislav
authors.initials: S
authors.lastname: Kopriva
mesh_terms: D000250:Adenosine Phosphosulfate / Q000737:chemistry; D000595:Amino Acid Sequence; D019068:Bryopsida / Q000201:enzymology*; D020134:Catalytic Domain; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D017433:Protein Structure, Secondary; D040681:Structural Homology, Protein; D013379:Substrate Specificity
chemical_list: D010940:Plant Proteins; D000250:Adenosine Phosphosulfate; D050862:Oxidoreductases Acting on Sulfur Group Donors; C019618:adenylylsulfate reductase
keywords: 3′-phosphoadenosine-5′-phosphosulfate; APR; APS; APS reductase; ASU; DLS; PAPS; Physcomitrella patens; Sulfate assimilation; Sulfonucleotide; X-ray structure; adenosine-5′-phosphosulfate; adenosine-5′-phosphosulfate reductase; asymmetric unit; dynamic light scattering